Augmented hemoperfusion for hyperbilirubinemia

Exchange transfusions and phototherapy are used to treat hyperbilirubinemia, each method having its own disadvantages. Hemoperfusion with coated activated charcoal (CAC) produces low removal rates due to the strong binding of bilirubin to albumin. Biocompatible chemical agents were investigated to selectively unbind the bilirubin into solution just prior to CAC exposure. In batch mock solution tests, the addition of sodium benzoate resulted in a 69% equilibrium bilirubin removal at 50 mM and 96% removal at 100 mM. During flow tests, adsorptive removal of sodium benzoate was so rapid that the CAC had to be pretreated with sodium benzoate solutions. In the absence of sodium benzoate, the outlet bilirubin was 50% of the inlet concentration at the passage of one void volume, with a rapid increase to 70% (30% removal). With sodium benzoate at 100 mM, the same 50% outlet/inlet percent was observed at one void volume throughput, but the outlet concentration fell to 6% of the inlet at 12 column void volumes (94% removal). Similar experiments with bovine plasma/blood and human plasma resulted in an average increase in bilirubin removal of 25% for the bovine and human plasma and 35% for the bovine blood at 100 mM benzoate. A significant decrease in platelet aggregation was measured with the addition of sodium benzoate, which makes this augmented hemoperfusion removal of bilirubin clinically attractive.